my pc crashed so had to reload everthing i had kentico 3.1a and now i downloaded 4

i have install IIS VWD adn sql server 2005 as well as kentico 4.0


when the kentico install is done i ran the http://localhost:1469/KenticoCMS/default.aspx

and got the following error

Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.

Compiler Error Message: CS0101: The namespace '<global namespace>' already contains a definition for 'UpgradeProcedure'

Source Error:

Line 25: /// Class carying the code to perform the upgrade procedure
Line 26: /// </summary>
Line 27: public static class UpgradeProcedure
Line 28: {
Line 29: /// <summary>


Source File: c:\Inetpub\wwwroot\KenticoCMS\App_Code\CMS\UpgradeProcedure.cs Line: 27

any help?